extracts FS interfaces into fsapi package and consolidates impls (#1477)

Signed-off-by: Adrian Cole <adrian@tetrate.io>
Signed-off-by: Edoardo Vacchi <evacchi@users.noreply.github.com>
Co-authored-by: Edoardo Vacchi <evacchi@users.noreply.github.com>

internal/sysfs/select_linux.go

@@ -0,0 +1,18 @@
+package sysfs
+
+import (
+	"syscall"
+	"time"
+
+	"github.com/tetratelabs/wazero/internal/platform"
+)
+
+// syscall_select invokes select on Unix (unless Darwin), with the given timeout Duration.
+func syscall_select(n int, r, w, e *platform.FdSet, timeout *time.Duration) (int, error) {
+	var t *syscall.Timeval
+	if timeout != nil {
+		tv := syscall.NsecToTimeval(timeout.Nanoseconds())
+		t = &tv
+	}
+	return syscall.Select(n, (*syscall.FdSet)(r), (*syscall.FdSet)(w), (*syscall.FdSet)(e), t)
+}